package com.walnut.lom_system.common.util;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/** */

/**
 * <p>
 * RSA公钥/私钥/签名工具包
 * </p>
 * <p>
 * 罗纳德·李维斯特（Ron [R]ivest）、阿迪·萨莫尔（Adi [S]hamir）和伦纳德·阿德曼（Leonard [A]dleman）
 * </p>
 * <p>
 * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
 * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
 * </p>
 * @author walnut
 * @version 1.0
 * @className DoLog
 * @description 请求数据解密
 * @date 2021/12/11 2:38 下午
 */
public class RSAUtil {

	/**
	 * 加密算法RSA
	 */
	public static final String KEY_ALGORITHM = "RSA";
	/**
	 * 签名算法
	 */
	public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
	/**
	 * 获取公钥的key
	 */
	private static final String PUBLIC_KEY = "RSAPublicKey";
	/**
	 * 获取私钥的key
	 */
	private static final String PRIVATE_KEY = "RSAPrivateKey";

	/**
	 * RSA最大加密明文大小
	 */
	private static final int MAX_ENCRYPT_BLOCK = 117;
	/**
	 * RSA最大解密密文大小
	 */
	private static final int MAX_DECRYPT_BLOCK = 128;

	/**
	 * RSA 位数 如果采用2048 上面最大加密和最大解密则须填写:  245 256
	 */
	private static final int INITIALIZE_LENGTH = 1024;

	/**
	 * <p>
	 * 生成密钥对(公钥和私钥)
	 * </p>
	 * 
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> genKeyPair() throws Exception {
		KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
		keyPairGen.initialize(INITIALIZE_LENGTH);
		KeyPair keyPair = keyPairGen.generateKeyPair();
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
		Map<String, Object> keyMap = new HashMap<String, Object>(2);
		keyMap.put(PUBLIC_KEY, publicKey);
		keyMap.put(PRIVATE_KEY, privateKey);
		return keyMap;
	}

	/**
	 * <p>
	 * 用私钥对信息生成数字签名
	 * </p>
	 * 
	 * @param data
	 *            已加密数据
	 * @param privateKey
	 *            私钥(BASE64编码)
	 * 
	 * @return
	 * @throws Exception
	 */
	public static String sign(byte[] data, String privateKey) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(privateKey);
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initSign(privateK);
		signature.update(data);
		return Base64.encodeBase64String(signature.sign());
	}

	/**
	 * <p>
	 * 校验数字签名
	 * </p>
	 * 
	 * @param data
	 *            已加密数据
	 * @param publicKey
	 *            公钥(BASE64编码)
	 * @param sign
	 *            数字签名
	 * 
	 * @return
	 * @throws Exception
	 * 
	 */
	public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(publicKey);
		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		PublicKey publicK = keyFactory.generatePublic(keySpec);
		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initVerify(publicK);
		signature.update(data);
		return signature.verify(Base64.decodeBase64(sign));
	}

	/** */
	/**
	 * <P>
	 * 私钥解密
	 * </p>
	 * 
	 * @param encryptedData
	 *            已加密数据
	 * @param privateKey
	 *            私钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(privateKey);
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, privateK);
		int inputLen = encryptedData.length;
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		int offSet = 0;
		byte[] cache;
		int i = 0;
		// 对数据分段解密
		while (inputLen - offSet > 0) {
			if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
				cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
			} else {
				cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
			}
			out.write(cache, 0, cache.length);
			i++;
			offSet = i * MAX_DECRYPT_BLOCK;
		}
		byte[] decryptedData = out.toByteArray();
		out.close();
		return decryptedData;
	}

	/** */
	/**
	 * <p>
	 * 公钥解密
	 * </p>
	 * 
	 * @param encryptedData
	 *            已加密数据
	 * @param publicKey
	 *            公钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(publicKey);
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key publicK = keyFactory.generatePublic(x509KeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, publicK);
		int inputLen = encryptedData.length;
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		int offSet = 0;
		byte[] cache;
		int i = 0;
		// 对数据分段解密
		while (inputLen - offSet > 0) {
			if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
				cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
			} else {
				cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
			}
			out.write(cache, 0, cache.length);
			i++;
			offSet = i * MAX_DECRYPT_BLOCK;
		}
		byte[] decryptedData = out.toByteArray();
		out.close();
		return decryptedData;
	}

	/** */
	/**
	 * <p>
	 * 公钥加密
	 * </p>
	 * 
	 * @param data
	 *            源数据
	 * @param publicKey
	 *            公钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(publicKey);
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key publicK = keyFactory.generatePublic(x509KeySpec);
		// 对数据加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, publicK);
		int inputLen = data.length;
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		int offSet = 0;
		byte[] cache;
		int i = 0;
		// 对数据分段加密
		while (inputLen - offSet > 0) {
			if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
				cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
			} else {
				cache = cipher.doFinal(data, offSet, inputLen - offSet);
			}
			out.write(cache, 0, cache.length);
			i++;
			offSet = i * MAX_ENCRYPT_BLOCK;
		}
		byte[] encryptedData = out.toByteArray();
		out.close();
		return encryptedData;
	}

	/** */
	/**
	 * <p>
	 * 私钥加密
	 * </p>
	 * 
	 * @param data
	 *            源数据
	 * @param privateKey
	 *            私钥(BASE64编码)
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {
		byte[] keyBytes = Base64.decodeBase64(privateKey);
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, privateK);
		int inputLen = data.length;
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		int offSet = 0;
		byte[] cache;
		int i = 0;
		// 对数据分段加密
		while (inputLen - offSet > 0) {
			if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
				cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
			} else {
				cache = cipher.doFinal(data, offSet, inputLen - offSet);
			}
			out.write(cache, 0, cache.length);
			i++;
			offSet = i * MAX_ENCRYPT_BLOCK;
		}
		byte[] encryptedData = out.toByteArray();
		out.close();
		return encryptedData;
	}

	/** */
	/**
	 * <p>
	 * 获取私钥
	 * </p>
	 * 
	 * @param keyMap
	 *            密钥对
	 * @return
	 * @throws Exception
	 */
	public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
		Key key = (Key) keyMap.get(PRIVATE_KEY);
		return Base64.encodeBase64String(key.getEncoded());
	}

	/** */
	/**
	 * <p>
	 * 获取公钥
	 * </p>
	 * 
	 * @param keyMap
	 *            密钥对
	 * @return
	 * @throws Exception
	 */
	public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
		Key key = (Key) keyMap.get(PUBLIC_KEY);
		return Base64.encodeBase64String(key.getEncoded());
	}

	/**
	 * java端公钥加密
	 */
	public static String encryptedDataOnJava(String data, String PUBLICKEY) {
		try {
			data = Base64.encodeBase64String(encryptByPublicKey(data.getBytes(), PUBLICKEY));
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return data;
	}

	/**
	 * java端私钥解密
	 */
	public static String decryptDataOnJava(String data, String PRIVATEKEY) {
		String temp = "";
		try {
			byte[] rs = Base64.decodeBase64(data);
			temp = new String(RSAUtil.decryptByPrivateKey(rs, PRIVATEKEY),"UTF-8");
		} catch (Exception e) {
			e.printStackTrace();
		}
		return temp;
	}

	public static void main(String[] args) throws  Exception{

		String privateKey = "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";
		String publicKey="MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCfXfMzgg4m5RRLg2vcrYBFN4sBhE1VtW1sBkXxC5wtCRaOZv0kudk9CIQfU6c+eEaaZKUnygxHWdSqdwURCE0IKgLcolXF+RHmu/rl977FfjRg9pAkBg5z05PfHDqWqkIsqX0iRaSP31BUZOgtwafbiBv2dBvRBMdq03ty4q8OQQIDAQAB";
		String data = encryptedDataOnJava("aaa", publicKey);
		String java = decryptDataOnJava("mYYGiqPJkv7uncpRtJpVqGrxKfZib4iYA5a8qI40gQmQy7A7IPXsn6mGj5suOmp9TmorHib9yddLmVw1iKUED5ua2Fuk5Cr3qcm6R TwMXMLNLJoLX1txns7XyfXdEJiANPcmPmiPzC2QA2hZVipuFe6aYXLZkc3Xj2qL2cIvZ4:", privateKey);
		System.out.println(java);
	}
}